scholarly journals Optimization of the firebox of a biomass-fired boiler

2021 ◽  
Vol 9 (3) ◽  
pp. 105-113
Author(s):  
Tamás Tolnai
Keyword(s):  
Solid Fuel ◽  
3D Model ◽  
Flow Characteristics ◽  
Operating Parameters ◽  
Optimized Design ◽  
Fuel System ◽  
Cfd Modelling ◽  
Plant Parts ◽  
Waste Solid ◽  
The Ideal

The most common fuel in crop drying is natural gas. Replacing this for renewable energy is both environmentally and economically beneficial. As a by-product of crop cleaning during harvesting, a source of energy suitable for combustion can be obtained from plant parts that are otherwise treated as waste. Solid fuel requires a special fuel system. Our goal is to find an optimized design for cleaning waste based on the existing solid fuel boilers, and in the framework of this work, the optimal design of the fire box passages is our narrower goal. To do this, we use CFD modelling, which is used to estimate the flow characteristics based on a 3D model in addition to the known operating parameters. By modifying the geometry between given boundaries, we find the ideal design within the boundaries allowed by the construction.

Characterisation of Static Strip Seal Flow

2007 ◽  
Author(s):  
Arash Farahani ◽  
Peter Childs
Keyword(s):  
Gas Flow ◽  
Pressure Ratio ◽  
Flow Characteristics ◽  
Main Stream ◽  
Cfd Modelling ◽  
Height Range ◽  
And Performance ◽  
Nozzle Guide ◽  
The Cost ◽  
Cooling Air

Strip seals are used in gas turbine engines between two static elements or between components which do not move relative to each other, such as Nozzle Guide Vanes (NGVs). The key role of a strip seal between NGV segments is sealing between the flow through the main stream annulus and the internal air system, a further purpose is to limit the inter-segmental movements. In general the shape of the strip seal is a rectangular strip that fits into two slots in adjacent components. The minimum clearance required for static strip seals must be found by accounting for thermal expansion, misalignment, and application, to allow correct fitment of the strip seals. Any increase in leakage raises the cost due to an increase in the cooling air use, which is linked to specific fuel consumption, and it can also alter gas flow paths and performance. The narrow path within the seal assembly, especially the height has the most significant affect on leakage. The height range of the narrow path studied in this paper is 0.01–0.06 mm. The behaviour of the flow passing through the narrow path has been studied using CFD modelling and measurements in a bespoke rig. The CFD and experimental results show that normalized leakage flow increases with pressure ratio before reaching a maximum. The main aim of this paper is to provide new experimental data to verify the CFD modelling for static strip seals. The typical flow characteristics validated by CFD modelling and experiments can be used to predict the flow behaviour for future static strip seal designs.

scholarly journals METHODS OF CFD MODELLING OF TWIN-SCREW PUMPS FOR NON-NEWTONIAN MATERIALS

2021 ◽  
Vol 2021 (6) ◽  
pp. 5366-5372
Author(s):  
MARIAN BOJKO ◽  
◽  
LUKAS HERTL ◽  
SYLVA DRABKOVA ◽  
◽  
...  
Keyword(s):  
Power Law ◽  
Food Industry ◽  
3D Model ◽  
Design Parameters ◽  
Cfd Modelling ◽  
Ansys Fluent ◽  
Screw Pump ◽  
Twin Screw ◽  
Definition Of ◽  
Power Law Parameters

The twin-screw pump is designed for pumping highly viscous materials in the food industry. Rheological characteristics of materials are important in the specification of design parameters of screw pumps. Analysis of flow in the twin-screw pumps with definition of non-newtonian materials can be made by numerical modelling. CFD generally oriented software ANSYS Fluent and ANSYS Polyflow has been used for modelling. In this study those software’s (ANSYS Fluent and ANSYS Polyflow) were defined for solution of flow in the twin-screw pumps. Results were compared for the same boundary conditions on the inlet and outlet of the 3D model. For definition of the viscosity were used the Nonnewtonian power law. Parameters as consistency coefficient and flow exponent for Nonnewtonian power law were analysed by software ANSYS Fluent and ANSYS Polyflow. Postprocessing form ANSYS Fluent and ANSYS Polyflow were made by contours of field and by graphs.

scholarly journals INTEGRATION OF SURVEYING TECHNIQUES TO DETECT THE IDEAL SHAPE OF A DOME: THE CASE OF THE ESCUELAS PÍAS CHURCH IN VALENCIA

2019 ◽  
Vol XLII-2/W9 ◽  
pp. 39-43
Author(s):  
S. Artese ◽  
J. L. Lerma ◽  
J. Aznar Molla ◽  
R. M. Sánchez ◽  
R. Zinno
Keyword(s):  
Laser Scanning ◽  
3D Model ◽  
Three Dimensional ◽  
Historical Building ◽  
Software Packages ◽  
Similarities And Differences ◽  
3D Documentation ◽  
Almost All ◽  
The Church ◽  
The Ideal

<p><strong>Abstract.</strong> The three-dimensional (3D) documentation and surveying of cultural heritage can be carried out following several geomatics techniques such as laser scanning and thermography in order to detect the original 3D shape after applying reverse engineering solutions. In almost all cases, the integration of data collected by different instruments is needed to achieve a successful and comprehensive 3D model of the as-built architectural shape of the historical building. This paper describes the operations carried out by the authors to determine the as-built 3D model of the Escuelas Pias Church, related namely to the dome and circular nave. After the description of the church and historical notes, attention will be driven to the indirect registration results obtained with three different laser scanning software packages, highlighting similarities and differences, and the consequences while generating meshes. The 3D model carried out will then be described and the results of some investigations with regard to the hypotheses about the design of the dome and the origin of the alterations will be presented.</p>

Survey of Digital Tools for the Generation of Ideas

2020 ◽  
Author(s):  
Marco Rossoni ◽  
Patrizia Bolzan ◽  
Giorgio Colombo ◽  
Monica Bordegoni ◽  
Marina Carulli
Keyword(s):  
3D Model ◽  
Present Moment ◽  
Technical Problems ◽  
Computer Tools ◽  
Initial Representation ◽  
New Ideas ◽  
Ideal Tool ◽  
New Research ◽  
High Degree ◽  
The Ideal

Abstract During the concept phase of the industrial design process drawings are used to represent designer’s ideas. More specifically, the designer’s goal is to put the characteristics of ideas on paper so that they can later act as pivotal points in the development of a project. Sketching is also the ideal tool to continue developing an idea: because it is imprecise, the sketch guarantees a high degree of freedom, allowing for changes to made and new ideas to be added. Another possibility is to translate ideas into sketches on computer tools. This approach can allow the designer to use the created 3D model as the basis for further developing ideas. At the present moment, however, this type of solution is not extensively used by designers during the concept phase. Some researchers have identified technical problems as the reason why these instruments have been unsuccessful on the market, while for others this is related to systems still too rigid to be adapted to the often-diverse needs of designers. The research presented in this position paper aims at analyzing what has so far been understood with respect to the process of generating ideas, their initial representation in the concept phase and the tools that have been developed so far to support this phase. Consequently, a discussion on these themes and some hypotheses from which develop new research lines will be presented.

Optimal Design of Basic Parameter of Disconnected Steering Trapezoid

2012 ◽  
Vol 424-425 ◽  
pp. 334-337
Author(s):  
Cui Xia Guo ◽  
Kang Liu ◽  
Wen Ling Xie
Keyword(s):  
Mathematical Model ◽  
Deflection Angle ◽  
Steering Wheel ◽  
Optimized Design ◽  
Pure Rolling ◽  
Tire Wear ◽  
Optimization Parameters ◽  
Basic Parameters ◽  
The Common ◽  
The Ideal

In the design of disconnected steering trapezoid, the Fmincon function of MATLAB optimization toolbox is used to optimize its basic parameters. First, establish the optimal mathematical model. Second, obtain wheel angle curve of inside and outside steering by least-squares fitting. Finally, compare the curve with the ideal Ackerman geometric curve to get the optimization parameters of disconnected steering trapezoid. The example of optimized design validated that the actual curve of deflection angle of the both sides of steering wheel was almost close to perfect Ackerman geometry curve, it ensures the steering of wheel do pure rolling in the common conditions, which reduce tire wear

scholarly journals Modelling of Fluid Flow and Residence Time Distribution in a Five-strand Tundish

2020 ◽  
Author(s):  
Dong-Yuan Sheng ◽  
Qiang Yue
Keyword(s):  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Volume Fraction ◽  
Fluid Dynamic ◽  
Flow Characteristics ◽  
Passive Scalar ◽  
Control Device ◽  
Dead Volume ◽  
Cfd Modelling

The quantified residence time distribution (RTD) provides a numerical characterization of mixing in the continue casting tundish, thus allowing the engineer to better understand the metallurgical performance of the reactor. This paper describes a computational fluid dynamic (CFD) modelling study for analyzing the flow pattern and the residence time distribution in a five-strand tundish. Two passive scalar transport equations are applied to separately calculate the E-curve and F-curve in the tundish. The numerical modelling results are compared to the water modelling results for the validation of the mathematical model. The volume fraction of different flow regions (plug, mixed and dead) and the intermixing time during the ladle changeover are calculated to study the effects of the flow control device (FCD) on the tundish performance. The result shows that a combination of the U-baffle with deflector holes and the turbulence inhibitor has three major effects on the flow characteristics in the tundish: i) reduce the extent of the dead volume; ii) evenly distribute the liquid streams to each strand and iii) shorten the intermixing time during the ladle changeover operation.

scholarly journals Experimental Investigation on the Hydraulic Characteristics of the Two-Phase Flow in the Intersecting Rock Fractures

Geofluids ◽  
2022 ◽  
Vol 2022 ◽  
pp. 1-14
Author(s):  
Chen Wang ◽  
Lujie Zhou ◽  
Yujing Jiang ◽  
Xuepeng Zhang ◽  
Jiankang Liu
Keyword(s):  
3D Model ◽  
Two Phase Flow ◽  
Rock Fracture ◽  
Flow Characteristics ◽  
Inertial Force ◽  
Fracture Network ◽  
Phase Flow ◽  
Hydraulic Characteristics ◽  
Two Phase ◽  
Flow Experiment

An appropriate understanding of the hydraulic characteristics of the two-phase flow in the rock fracture network is important in many engineering applications. To investigate the two-phase flow in the fracture network, a study on the two-phase flow characteristics in the intersecting fractures is necessary. In order to describe the two-phase flow in the intersecting fractures quantitatively, in this study, a gas-water two-phase flow experiment was conducted in a smooth 3D model with intersecting fractures. The results in this specific 3D model show that the flow structures in the intersecting fractures were similar to those of the stratified wavy flow in pipes. The nonlinearity induced by inertial force and turbulence in the intersecting fractures cannot be neglected in the two-phase flow, and the Martinelli-Lockhart model is effective for the two-phase flow in intersecting fractures. Delhaye’s model can be adapted for the cases in this experiment. The turbulence of the flow can be indicated by the values of C in Delhaye’s model, but resetting the appropriate range of the values of C is necessary.

scholarly journals Design, Simulation, and Experiment of an LTCC-Based Xenon Micro Flow Control Device for an Electric Propulsion System

Processes ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 862 ◽  
Author(s):  
Chang-Bin Guan ◽  
Yan Shen ◽  
Zhao-Pu Yao ◽  
Zhao-Li Wang ◽  
Mei-Jie Zhang ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Flow Control ◽  
Electric Propulsion ◽  
Flow Characteristics ◽  
Control Device ◽  
Microfluidic Channels ◽  
Optimized Design ◽  
Element Analysis ◽  
Flow Control Device ◽  
Micro Flow

A xenon micro flow control device (XMFCD) is the key component of a xenon feeding system, which controls the required micro flow xenon (µg/s–mg/s) to electric thrusters. Traditional XMFCDs usually have large volume and weight in order to achieve ultra-high fluid resistance and have a long producing cycle and high processing cost. This paper proposes a miniaturized, easy-processing, and inexpensive XMFCD, which is fabricated by low-temperature co-fired ceramic (LTCC) technology. The design of the proposed XMFCD based on complex three-dimensional (3D) microfluidic channels is described, and its fabrication process based on LTCC is illustrated. The microfluidic channels of the fabricated single (9 mm diameter and 1.4 mm thickness) and dual (9 mm diameter and 2.4 mm thickness) XMFCDs were both checked by X-ray, which proved the LTCC method’s feasibility. A mathematical model of flow characteristics is established with the help of finite element analysis, and the model is validated by the experimental results of the single and dual XMFCDs. Based on the mathematical model, the influence of the structure parameters (diameter of orifice and width of the groove) on flow characteristics is investigated, which can guide the optimized design of the proposed XMFCD.

Comparison of Light Fuel-Oil Fractions Produced by Semicoking of Kukersite Shale in a Gas Generator and in a Solid-Fuel System

2019 ◽  
Vol 62 (6) ◽  
pp. 249-257 ◽  
Author(s):  
N. I. Petrovich ◽  
N. N. Ostroukhov ◽  
V. V. Vasilyev ◽  
E. V. Salamatova ◽  
V. M. Strakhov
Keyword(s):  
Solid Fuel ◽  
Fuel Oil ◽  
Fuel System ◽  
Gas Generator ◽  
Oil Fractions

Numerical Investigation Into Fully and Partially Wetted Disk Geometries With Relevance to Intershaft Hydraulic Seals

2020 ◽  
Author(s):  
Achinie Warusevitane ◽  
Kathy Johnson ◽  
Stephen Ambrose ◽  
Mike Walsh ◽  
Colin Young
Keyword(s):  
Fluid Dynamic ◽  
Tangential Velocity ◽  
Flow Characteristics ◽  
Rotating Disk ◽  
Radial Pressure ◽  
Experimental Investigations ◽  
Published Data ◽  
Cfd Modelling ◽  
Validation Data ◽  
Rotating Shafts

Abstract Civil aero-engines contain two or three shafts that are supported by bearings. Seals are required both between pairs of rotating shafts and between static elements and shafts. Seals located between two co/contra rotating shafts within the bearing chamber are known as intershaft seals and are typically classified as either hydraulic or oil backed. This paper focuses on research relevant to intershaft hydraulic seals. A hydraulic seal is formed by a seal fin on the inner shaft immersed in an annulus of oil in the outer shaft where the oil in the annulus is centrifuged outwards by the radial pressure gradient. Once formed a hydraulic seal does not allow air to flow across the seal and any pressure difference across the seal creates different oil levels either side of the fin. Despite their reliable operation with zero leakage, the application of hydraulic seals is restricted due to temperature limitations, oil degradation and coking. Research and development of the next generation of hydraulic seals needs to focus on addressing these issues so that the seals can be utilized in hotter zones in future engines. Understanding of the detailed fluid dynamic behaviour during hydraulic seal operation is relatively limited with very little published data. There is an acknowledged need for improved knowledge and this is the context for the current study. The ability to accurately computationally model hydraulic seals is highly desirable. Prior experimental and analytical investigations into fully and partially wetted rotating disks have been used to aid understanding of the performance and flow characteristics of hydraulic seals as there are many geometric and operational similarities. These fundamental experimental investigations in the literature provide validation data that allows the authors to establish a CFD modelling methodology. This paper initially compares the flow characteristics of a fully wetted rotating disk against experimental results available in literature including the radial and tangential velocity components. This paper subsequently investigates the flow characteristics of a partially wetted disk by examining the effect on the angular velocity of the fluid core with varying engagement and spacing ratios for two flow regimes.

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